4.53 In the capacitor-coupled attenuator circuit shown in Fig. P4.53, I is a dc current that varies from 0 mA to 1 mA, and C1 and C2 are large coupling capacitors. For very small input signals, so that the diodes can be represented by their small-signal resistances rd1 and rd2, give the small-signal equivalent circuit and thus show that and hence that , where I is in mA. Find vo/vi for I = 0 µA, 1 µA, 10 µA, 100 µA, 500 µA, 600 µA, 900 µA, 990 µA, and 1 mA. Note that this is a signal attenuator whose transmission is linearly controlled by the dc current I. Figure P4.53 0 V/V; 0.001 V/V; 0.01 V/V; 0.1 V/V; 0.5 V/V; 0.6 V/V; 0.9 V/V; 0.99 V/V